Evaluation of HER2 protein expression in gastric carcinomas: comparative analysis of 1,414 cases of whole-tissue sections and 595 cases of tissue microarrays.

Despite discrepancies in the results from whole-tissue sections and TMAs, HER2 overexpression was positively correlated with aggressive biological behavior and was an independent poor prognostic factor for recurrence in differentiated GCs. Therefore, HER2-positive GCs should be considered for adjuvant trastuzumab therapy.